In a conventional type of shelf support, brackets are provided in the form of plates having projecting portions at a rearward end thereof for locking engagement into slots provided on elongated supports which are screwed or otherwise secured to a wall. This type of shelf support has been generally satisfactory in many cases and has been widely used but has had disadvantages including the fact that the number of obtainable vertical levels of the brackets is limited by the number of slots in the elongated supports. Also, the supports must be carefully installed to insure that the slots therein are all at the same levels since otherwise the shelves may be inclined. When a shelf overlies three or more brackets along its length, there is a possibility that it will be supported by less than all of such brackets if the elongated supports are not accurately mounted.
Proposals have been made for providing infinitely adjustable brackets of various types. The arrangements as proposed have been relatively complicated and have been such that there is a possibility that the shelves will not be securely and reliably supported, especially if the brackets are not carefully installed. They have been such that installation of the brackets is difficult and time-consuming and the brackets and supporting structures have been expensive to manufacture.